I purchased the Charging base at the same time that I purchased my Scooba a few years ago. At the time I bought it because I did not have a place to keep my floor washing robot plugged in and charged so it would be ready at all times. I did have a spot where I could keep the charging base, so it was essentially a space saving maneuver.
The base is a bit clunky and takes up a chunk a little larger than the size of the battery plus of course you will have the battery attached. It comes with a charging cord that has a rather large power supply attached.
How to use the Charging Base
To charge your battery simply line up the connectors and set it into the charger. It does not snap in, it just stays in place with the weight of the battery. It has two lights going. One lets you know that the unit is plugged in and operational and the other lets you know that the battery is charging. The battery charging will stop once the battery is fully charged but the charger will keep it ready to go for you. Still I always reset the battery in the charger the night before I am going to use my Scooba.
How well it Works
I think I have had my scooba with the same battery for at least three years. I did not use it for awhile because we had cleaning ladies doing our cleaning for a bit but the battery sat on the charger. We had to let the cleaning ladies go recently so I was back to cleaning myself and out came Scooba. I was amazed that after all that time of not using it that my robot and battery were still cleaning for a good amount of time.
I later read that some people who were not using the external charger were experiencing dead batteries much sooner and that by keeping it sitting on the charger it actually extends the life of the battery. Well lucky for me, my battery had been sitting on the charger all that time so I have a fully functioning floor washing robot.
Cost and Value
I feel that even though the price of the Scooba Charging base is a bit steep at around $60, it was worth it because besides providing a convenient way to charge my battery, it seems to have prolonged the life of my battery.
Final Thoughts and Rating
One other thing to consider. A lot of people buy the charging base and an extra battery. If you do this you have to plug in both your Scooba and your Charging base somewhere and keep them plugged in. If I had enough hard floors that I required a second battery I would suggest buying two charging bases. What would be awesome is if iRobot made a double charging base that would power up with one cord. Nifty idea huh?
I will give the Charging base 4 stars. I am taking off a star because iRobot could not figure out a way to put the transformer inside the charging base or make it less clunky. I would rather have just one thing to plug into the wall rather than multiple pieces of the same thing.